• Steel and Composite Structures
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• 제21권4호
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• pp.949-962
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• 2016

The braking hose in the automotive hydraulic braking system exhibits the complicated anisotropic large deformation while its movable end is moving along the cyclic path according to the steering and bump/rebound motions of vehicle. The complicated large deformation may cause not only the interference with other adjacent automotive parts but also the durability problem resulting in the fatal microcraking. In this regard, the design of high-durable braking hose with the interference-free layout becomes a hot issue in the automotive industry. However, since it has been traditionally relied on the cost-/time-consuming trial and error experiments, the cost- and time-effective optimum design method that can replace the experiment is highly desirable. Meanwhile, the hose deformed configuration and fatigue life are different for different hose cyclic paths, so that their characteristic investigation becomes an important preliminary research subject. As a preliminary step for developing the optimum design methodology, we in this study investigate the hose deformed configuration and the fatigue life for four representative hose cyclic paths.

• 청정기술
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• 제23권1호
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• pp.15-26
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• 2017

폐자동차는 재활용 자원의 주요 원천이며 폐자동차 재활용 과정은 해체, 파쇄 및 ASR 처리 단계로 구분된다. 폐자동차 해체는 재사용 가능 부품을 수집하는 등 매우 중요한 단계인데, 크게 독립형(island type)과 라인형(line type) 으로 구분할 수 있고 다양한 유형의 해체 시스템이 존재한다. 또한 국가별 법적 규제, 폐자동차 발생량, 인구밀도, GNP 등 국가 별 특성이 다르기 때문에 특성에 맞는 적절한 해체 시스템을 체계적으로 선정하는 방법이 필요하다. 본 연구에서는 퍼지이론 및 변형 QFD를 활용하여 국가 특성에 대한 데이터 퍼지화 및 해체시스템 적합도를 평가하는 방법을 개발하였으며, 관련 데이터를 보유한 대표 국가에 대해 적용하고 결과를 평가하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제27권1호
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• pp.76-81
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• 2003

The purpose of this study is to analyze the collapse characteristics of widely used spot welded section members coated damping material Y1000 and to develop an analysis method for acquiring exact collapse loads and energy absorption ratio. Hat-shaped thin-walled members have the biggest energy absorbing capacity in a front-end collision. The sections were tested on quasi-static and impact loads. Specimens with two type thickness, width ratio and spot weld pitch on the flange have been tested in impact velocities(6.73n0sec and 7.54n1sec) which imitate a real-life car collision. As a result, it was developed the system for acquiring impact energy absorbing characteristics of structure united thin-walled member and damping materials.

• Journal of Biosystems Engineering
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• 제33권1호
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• pp.38-44
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• 2008

The freight vehicle is mostly used to transport the fruit. Shock and impact generated by the freight vehicle may give serious damage to fruits hence to reduce the fruits damage, the optimum packaging design during transportation by vehicle is required. In order to design the packaging system for fruit transportation optimally, the comprehension of characteristic for vibration and shock acting on vehicles under various road conditions and loading methods is required. This research was performed to analyze the shock characteristics, acceleration level and power spectral density (PSD) of the fruit transportation vehicles under several travel roads and positions. The vibration signal was measured and analyzed at the transportation vehicle operating on the road of three different surface conditions. The maximum acceleration was measured at the rear-end of the vehicle, and the acceleration in the direction of up-and-down (z-axis) was much greater than those in the directions of back-and-forth (x-axis) or right-and-left (y-axis). The peak acceleration in the direction of up-and-down (z-axis) at the vehicle driving on the expressway, the local road paved with concrete, and unpaved local road were 5.3621 G, 8.232 G, and 14.162 G respectively. PSD at 2.44 Hz showed maximum value at all road conditions. The maximum values of PSD on the expressway, a local road paved with concrete, and unpaved local road were 0.0075222 $G^2/Hz$, 0.058655 $G^2/Hz$, and 0.24598 $G^2/Hz$ respectively. The value of PSD decreased with an increase of the vibration frequency of the transportation vehicle. In most cases, the vibration frequency was below 20 Hz during transportation.

• 정보처리학회논문지:컴퓨터 및 통신 시스템
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• 제12권10호
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• pp.309-318
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• 2023

최근 세계 각국은 온실가스 배출을 규제하기 위해 전과정평가(LCA, Life Cycle Assessment)를 도입하려는 움직임을 보이고 있다. 전기차 전과정평가는 차량의 전체 수명주기에 걸쳐 발생하는 온실가스 배출량을 측정하고 평가하는 수단이다. 전과정평가 결과의 신뢰성을 높이기 위해서는 전기차 부품별로 신뢰성 있는 데이터가 필요하다. 이를 위해 최근 블록체인 기술을 적용한 전과정평가 모델에 대한 연구들이 수행되었다. 그러나 기존 연구들은 주요 제품 정보들이 다른 참여자들에게 그대로 노출되어 프라이버서 보호가 되지 않는 문제가 있고 부품데이터 정보가 업데이트될 때마다 트랜잭션 형태로 블록체인 원장에 기록해야 해서 비효율적이다. 따라서 본 논문에서는 효율적으로 전기차 차량부품 데이터를 수집하고 유효성을 검증하기 위해 전과정평가를 위한 DID 기반의 데이터수집 모델을 제안한다. 제안하는 모델은 수집된 데이터의 유효성과 무결성을 보장하며 블록체인 원장에는 사용자 인증 정보만 공유되어 데이터의 무분별한 노출을 방지하고 데이터의 출처를 효율적으로 검증 및 업데이트할 수 있다.

• 한국기계가공학회지
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• 제20권5호
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• pp.128-134
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• 2021

A press-fitted shaft is an essential part used in industrial machines, and it is generally used to transmit large quantities of power. Very high contact pressure occurs at the end parts of the contact between the shaft and boss, which are press-fitted shaft components. Such contact pressure not only damages the contact surface of a press-fitted shaft but also reduces its fatigue strength. To improve a press-fitted shaft's fatigue strength, the contact pressure on the contact surface, which directly affects the fatigue strength, should be minimized. Thus, in this study, the design configuration optimization of the end part of the boss was based on the approximate optimization method and was aimed at minimizing the contact pressure at the end of a press-fitted shaft. Comparison of the contact pressure and the contact stress of a conventional press-fitted shaft with those of the optimized press-fitted shaft showed that the boss design of the optimized press-fitted shaft effectively improved the fatigue life.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2009년도 춘계학술대회 논문집
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• pp.653-658
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• 2009

This paper describes the structural deflection analysis method and result of EMU(Electric Multiple Units). During manufacturing of rail passenger coaches, the underframe is assigned a camber before it is integrated with other major assemblies of shell such as the side panel, the end panel and the roof. The camber of the positive deflection given intentionally to compensate for the sagging so that it remains straight at the maximum load. But some manufacturers have insisted there has no relationship between the camber and the safety or life cycle and they expect to reduce a manufacturing cost without a camber. So this study analyzes whether the camber influences on the safety or life cycle of EMU structure under a full load and regular driving condition. The structural dynamics model for a railway vehicle is introduced.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2019년도 추계학술대회
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• pp.216-217
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• 2019

The battery powered electric vehicle (EV) is one of most promising technologies in 21^st century. Though the lithium batteries are playing an important role in the EVs, they are only applicable until their capacities reach 80%, the end of its useful first life. Yet, these batteries can live a second life such as Energy Storage Systems (ESS). In order to utilize the Residual Useful Life (RUL) of the batteries the State of Health (SOH) of them needs to be estimated by a nondestructive test such as Electrochemical Impedance Spectroscopy (EIS) technique. Though many kinds of different EIS instruments are commercially available, most of them can only test a battery module less than 10V and the price of the instrument is very high. In this paper a low-cost EIS instrument suitable for measuring the impedance spectrum of the high voltage battery module is proposed and its validity is verified through the experiments. In order to prove the accuracy of the developed EIS instrument its measured impedance spectrum is compared with the results obtained by a commercial instrument. The Chi Square value calculated between two impedance spectrum measured by both developed and commercial instruments are less than 2%, which prove the strong correlation between two results.

• International Journal of Control, Automation, and Systems
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• 제6권3호
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• pp.351-363
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• 2008

This paper is concerned with tasking and guidance of networked airborne sensors to achieve fault-tolerant sensing. The sensors are coordinated to locate hostile transmitters by intercepting and processing their signals. Faults occur when some sensor-carrying vehicles engaged in target location missions are lost. Faults effectively change the network architecture and therefore degrade the network performance. The first objective of the paper is to optimally allocate a finite number of sensors to targets to maximize the network life and availability. To that end allocation policies are solved from relevant Markov decision problems. The sensors allocated to a target must continue to adjust their trajectories until the estimate of the target location reaches a prescribed accuracy. The second objective of the paper is to establish a criterion for vehicle guidance for which fault-tolerant sensing is achieved by incorporating the knowledge of vehicle loss probability, and by allowing network reconfiguration in the event of loss of vehicles. Superior sensing performance in terms of location accuracy is demonstrated under the established criterion.

• 한국전기전자재료학회논문지
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• 제31권6호
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• pp.422-426
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• 2018

The lithium-ion battery pack of an electric vehicle (EV) deserves to be considered for an alternative use within smart-grid infrastructure. Despite the long automotive service life, EV batteries retain over 70~80% of their initial capacity. These battery packs must be managed for their reliability and safety. Therefore, a battery management system (BMS) should use specific algorithms to measure and estimate the status of the battery. Most importantly, the BMS of a grid-connected energy storage system (ESS) must ensure that the lithium-ion battery does not catch fire or explode due to an internal short from uncontrolled dendrite growth. In other words, the BMS of a lithium-ion battery pack should be capable of detecting the battery's status based on the electrochemical reaction continuously until the end of the battery's lifespan. In this paper, we propose a new protection algorithm for a dendritic lithium battery. The proposed algorithm has applied a parameter from battery pack aging results and has control power managing.